Amalgam of Platinum. — Iodide of Mercury. 263 



Platinum, - - - 

 Chlorine, - - - 

 Water, - - 



24.6400 100.000 



The atomic proportion of the water can now be determined. 



Pl.-}-2Cl.+ Aq. PI.+2C1. P1.+2CI. Aq. P1.+2C1. 



24.64 : 15.8824 : : 21 + a; : 21 whence a; = 1 1 .57 

 Thomson's atomic number for water is 1.125. The number of 

 atoms of water there in tlie hydrated bichloride of platinum is 

 lO-rVo = V.tV/* The compound when crystallized, was not ob- 

 served to be moist, but the atoms come out so near to 10, that it 

 may be considered as composed of 



Platinum, 1 atom, - - - - 12 37.21 



Chlorine, 2 atoms ... - 9 27.90 



Water, 10 atoms, - - - - 11.25 34.89 



32.25 100.00 



IX. Amalgam of Platinum. 



Muschin Pushkin describes an easy method of forming this amal- 

 gam. It may be more conveniently and quickly formed by heating 

 the chloriodide of platinum with mercury in a tube. The iodine and 

 chlorine combine with mercury and sublime, while the platinum 

 in its nascent state combines with mercury, and remains in the bot- 

 tom of the tube. The heat should be high enough to make the 

 mercury boil. The amalgam after having been pressed in soft leath- 

 er, to remove the excess of mercury, is a soft solid, having the same 

 kind of feel, and emitting the same sound when pressed between the 

 fingers, as the amalgams of gold and silver. It is several times heav- 

 ier than the platinum of which it was formed. 



X. Iodide of Mercury. 



The iodide of mercury may be dissolved in hydriodic acid, which 

 I have found a good solvent. Hydriodate of potassa is mentioned 

 in some chemical authors, as a good solvent for iodide of mercury. 



Iodide of mercury when fused, is of a dark color, volatilizes of a 

 beautiful yellow, when the fused portion is congealing it is of a fine 

 red, and when cold yellow. Solution of potassa changes the yellow 

 to red, but does not decompose it. It seems from what precedes, 

 that the color of the iodide of mercury, is dependent on the state 

 of aggregation. 



